Background: the objective of this study was to correlate the presence of leptomeningeal venous. drainage and dysplastic venous dilation with the risk of intracranial hemorrhage in DAVFs.Methods: the subjects for this research were composed of 93 patients with DAVFs who were studied retrospectively with regard to therapeutic success and failure, who had undergone either neurosurgery or embolization or a combination of both methods, and whose disease was located in the cavernous sinus, the superior sagittal sinus, or the transverse-sigmoid sinus of the anterior fossa or of the tentorium. Also among these study subjects were patients who had had angiography done in at least 6 cranial vessels (external and internal carotid and vertebral arteries) before and after treatment and who had a minimum follow-up of 3 months. Cases of leptomeningeal venous drainage and dysplastic venous dilation and their associations with intracranial hemorrhage were ascertained for all the 93 case patients included in the study.Results: the presence of leptomeningeal drainage (P = .0002) and that of dysplastic venous dilation (P = .036) increased the risk of intracranial hemorrhage in case patients for DAVFs of the 5 regions.Conclusion: There is a statistical significance between risk of intracranial hemorrhage in DAVFs and the presence of leptomeningeal drainage and dysplastic venous dilation. (c) 2006 Elsevier Inc. All rights reserved.